Antifoam/defoamer composition

ABSTRACT

An antifoam/defoamer composition a polyether surfactant and a polyhydric alcohol fatty acid ester. The polyether surfactant being admixed with the polyhydric alcohol fatty acid ester in a ratio in the range between 10:90 to 90:10% by weight.

This is a continuation of application Ser. No. 238,382, filed 8/31/88now abandoned.

BACKGROUND OF THE INVENTION

A unique antifoam/defoamer composition is provided having concentratedactive ingredients, such as a polyether surfactant and a polyhydricalcohol fatty acid ester. This composition is particularly advantageousfor foam control and drainage enhancement in the following applications:paper and pulp processes, general wet-end foam control,groundwood/mechanical pulp systems, secondary fiber systems, and bleachplants/screen rooms.

Foam is consistently a problem in the processing of pulp during themanufacture of paper products. Virtually all segments of the papermakingprocess generate entrained air and surface foam which are extremelyundesirable due to their deleterious effect upon process efficiency andthe finished product.

A variety of antifoam/defoamer agents have been used with varyingdegrees of success. Many defoamers are stearic acid or fatty acid basedemulsion products. Some examples of stearic acid based emulsion productsare set forth in the following patents: U.S. Nos. 3,705,860(Duvall),issued Dec. 12, 1972, and 3,337,595.

Typical fatty acid based emulsion products are described in thefollowing patents: Great Britain Patent Appl. No. 81/29520 (Flannigan),filed Sept. 30, 1981, European Patent Appl. No. EP 76558 (Flannigan),filed Apr. 13, 1983, French Pat. No. 1557086, issued Feb. 14, 1969,German Patent Appl. No. DE 3013292 (Perner et al.), published Oct. 15,1981, and U.S. Pat. No. 4,451,390 (Flannigan), issued May 29, 1984.

Antifoam products are usually sold in diluted form causing them to bebulky and costly to transport. These defoaming agents may also containundesirable particulate additives Which may deposit throughout thepapermaking process resulting in undesirable deposits throughout thesystem. Particulate additives Which may cause deposits and plugging ofpapermaking systems are typically stearic acids, fatty acids, silicones,hydrophobic silica, waxes or other organic particles

Other examples of defoamer agents Which contain particulate additives,such as silicone, hydrocarbons or other organic particles, are asfollows: Great Britain Patent Appl. No. 2,094,330 (Topfl et al.), filedSept. 15, 1982, German Patent Appl. No. 2,625,707 (Abel et al.),published Dec. 23, 1976, Japanese Patent Appl. No. 50,404/79 (Hirakimotoet al.), published May 14, 1979, and Romanian Patent Appl. No. 111,852(Deac et al.), filed Aug. 5, 1983.

The present inventor has developed a unique antifoam/defoamercomposition which substantially reduces transportation costs andovercomes deposition problems associated with the aforementioneddefoaming agents. It avoids the problems associated with conventionalantifoam products by forming a concentrate of active ingredients, suchas a polyether surfactant and a polyhydric alcohol fatty acid ester,without any oil, amide, hydrophobic silica or silicone additives.

The use of glycols or glycerols as foam inhibiting agents is describedin the following patents: Japanese Patent Appl. No. 79/59404 (Hirakimotoet al.), published May 14, 1979, French Patent No. 2,049,783(Seizinger), granted Apr. 30, 1971, French Patent No. 1,557,086, grantedFeb. 14, 1969, and Japanese Patent Publication No. 75/005,157, publishedFeb. 28, 1975.

Hirakimoto et al. describe a defoaming agent which includes a polyetherwith a molecular weight of 2000-16,000, the polyether being prepared bypolymerization of ethylene oxide (5-30 parts) and propylene oxide (95-70parts) and reaction with a polyol, such as glycerol or sorbitol;2-ethylhexyl alcohol; and a paraffin oil.

Seizinger describes a nonionic, biodegradable foam inhibitor used indetergents, latexes, and paper manufacturing. The inhibitors areprepared from mixtures of alkylene oxide, glycol, and a polymercatalyst. The catalyst is prepared by heating glycerol in KOH, removingwater, and adding propylene oxide under nitrogen. Theoxide/glycol/catalyst mixture was thereafter heated, and the catalystwas removed to give a yellow liquid inhibitor.

French Pat. No. 1, 557,086 describes an antifoaming agent for use infoam prevention by reaction products with blockpolyethylene-polypropylene glycols and polyols.

Japanese Patent Publication No. 75/005,157 describes a defoaming agentcontaining a higher aliphatic ester compound and emulsifier for use inpapermaking, fiber, paint, and fermentation industries.

The present invention is a concentrated, active, emulsifiable productwhich has many cost saving advantages over conventional defoamers. Beinga pure active ingredient, the defoamer of the present invention has nobase or carrier resulting in reduced transportation and container costs.Furthermore, the fact that this defoamer is not an oil-based defoamerassists in preventing the loss of paper sheet properties, such asbrightness, sizing efficiency and strength. Having no oil, amide,hydrophobic silica or silicone additives prevents deposition and feltfilling. It has also been discovered that the defoamer composition ofthe present invention is a much more effective agent for control ofentrained air than conventional defoaming agents. Additional advantagesof the present invention shall become apparent as described below.

SUMMARY OF THE INVENTION

The present invention provides an antifoam/defoamer compositioncomprising a polyether surfactant and a polyhydric alcohol fatty acidester. The polyether surfactant is mixed with the polyhydric alcoholfatty acid ester in a ratio in the range between about 10:90 to 90:10percent by weight.

The polyether surfactant contains at least one compound selected fromthe group consisting of polyoxyalkylated glycerol, polyoxyalklatedsorbitol or sorbitan, polyoxyalklated sucrose, and isomers thereof.Furthermore, the polyoxyalklated glycerol, sorbitol or sucrose containethylene oxide in the range between about 0-60 weight percent and/orpropylene oxide in the range between about 30-100 weight percent, andhas a molecular weight in the range between about 1000-10,000. It ispreferable that the polyether surfactant have a HLB in the range betweenabout 6-12, preferably 7-10.

More specifically, the polyether surfactant includes a glycerolheteropolymer or block copolymer with ethylene oxide and/or propyleneoxide in an amount such that the total molecular weight of the polyethersurfactant is about 1000-8000 and such that it contains between about0-30% ethylene oxide by weight.

The polyhydric alcohol fatty acid ester is typically a polyethyleneglycol ester of fatty acids prepared by either oxyalkylation oresterification. Preferably, the polyethylene glycol ester contains fromabout 1 to about 20 moles of ethylene oxide The polyethylene glycolester is a diester of fatty acids. More preferably, the polyethyleneglycol ester is a 200-600 mono and/or diesters of oleic, tall oil, orstearic acids. Furthermore, the polyhydric alcohol fatty acid estercontains between about 1-20 moles of ethylene oxide and/or propyleneoxide.

The polyethylene glycol ester is obtained by reaction of a fatty acid,such as, oleic, tall oil or stearic acid with polyethylene glycol liquidand solid polymers of the general formula H (OCH₂ CH₂)_(n) OH, where nis between about 3 to about 10 or a mixture of the polyethylene glycolesters.

An additional object of the present invention is a method forcontrolling foam in a papermaking process which includes the step ofadding to a pulp slurry, papermaking furnish, and/or pulp suspension anantifoam/defoamer composition comprising a polyether surfactant and apolyhydric alcohol fatty acid ester. The antifoam/defoamer compositionis added at a concentration in the range between about 0.01-10.0lbs./ton of paper produced, preferably in a range between about 0.10-3.0lbs./ton of paper produced. The present invention may also include manyadditional features which shall be further described below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph which plots foam column height versus time for apolyether surfactant, an emulsifier for the polyether surfactant(emulsifier Z), and the defoamer composition of the present invention(defoamer Y) to determine antifoam characteristics thereof;

FIG. 2 is a graph which plots foam column height versus the number ofdrops of a polyether surfactant, emulsifier Z, and the defoamercomposition of the present invention (defoamer Y) to determine defoamingcharacteristics thereof;

FIG. 3 is a graph which plots foam number versus dosage (ppm) for a 100%active propoxylated fatty alcohol defoamer (defoamer R) and the defoamercomposition of the present invention (defoamer Y);

FIG. 4 is a graph which plots foam height versus time for a water-basedemulsion defoamer (defoamer S), a polyether surfactant, a polyethyleneglycol ester, and the defoamer composition of the present invention(defoamer Y); and

FIG. 5 is a graph which plots defoamer flow versus entrained air levelsfor a defoamer A, an oil-based particulate containing concentrateddefoamer B, a polyether surfactant, a water-based silica/amide defoamerC, a fatty alcohol water-based particulate defoamer D, and the defoamercomposition of the present invention (defoamer Y).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an antifoam/defoamer concentrate havingsuperior activity and cost/performance than conventional oil or waterbased defoamers. It is highly effective in reducing or eliminatingentrained air and surface foam in many pulp and paper process streams.Furthermore, the defoamer composition of the present invention does notcontain oil, amides, hydrophobic silica or silicone additives, therebyavoiding deposition and felt filling problems.

Examples of some applications in which this defoamer compositionprovides particularly good foam control and drainage enhancement are asfollows: general wet-end foam control, groundwood/TMP systems, secondaryfiber systems, bleach plants/screen rooms, and effluent streams.

The antifoam/defoamer composition of the present invention comprises apolyether surfactant and a polyhydric alcohol fatty acid ester. Thepolyether surfactant is mixed with the polyhydric alcohol fatty acidester in a ratio in the range between about 10:90 to 90:10 percent byweight, preferably 25;75 to 75:25 percent by weight. The polyethersurfactant has a HLB in a range between about 6-12, preferably betweenabout 7-10.

The polyether surfactant includes at least one compound selected fromthe group consisting of polyoxylalklated glycerol, sorbitol or sorbitan,sucrose, and isomers of these polyhydric alcohols.

The polyhydric alcohol fatty acid ester includes a polyethylene glycolmono and/or diesters of fatty acids prepared by oxyalkylation oresterification of fatty acids. In particular, the ester may bepolyethylene glycol 100-800 mono and/or diesters of fatty acids. Apreferred ester is polyethylene glycol 200-600 mono and/or diesters ofcommercial quality oleic, tall oils, or stearic acids. Commerciallyavailable polyhydric alcohol fatty acid esters are sold under thetrademarks KESSCO (polyethylene glycol ester) by Stepan Chemical Companyand EMEREST (polyethylene glycol ester ) by Emery Chemical IndustriesInc.

Preferably, the polyethylene glycol ester contains from about 1 to about20 moles of ethylene oxide. The polyethylene glycol ester is obtained byreaction of a fatty acid, such as, oleic, tall oil or stearic acid withpolyethylene glycol liquid and solid polymers of the general formula H(OCH₂ CH₂)_(n) OH, where n is between about 3 to about 10 or a mixtureof the polyethylene glycol esters. The term oleic as used herein shallinclude oleic, linoleic, linolenic, or combination thereof. The termstearic acid as used herein shall include stearic and/or palmitic acids.

Optionally, the polyhydric alcohol fatty acid ester may have a chemicalmake-up which includes a fatty acid mono and/or diesters of polyethyleneand/or polypropylene glycols reacted with oleic, tall oil or tallowderived fatty acids.

The polyhydric alcohol fatty acid ester may also include fatty acidesters of other polyhydric alcohols, such as, glycerol, sorbitol orsorbitan, sucrose, and isomers of these alcohols. Fatty acids reactedwith these alcohols include oleic, tall oil, castor oil and tallowderived fatty acid. These fatty acid esters may be further modified withalkoxylation. Commercially available surfactants are sold under thetrademarks SPAN, TWEEN, ARLACEL, ARLATONE, and MYRJ by ICI Americas.

As an example, a preferred antifoam/defoamer composition in accordancewith this invention includes a polyoxyalkylated glycerol, sorbitol orsucrose containing about 0-60 weight percent ethylene oxide and/or about30-100 weight percent propylene oxide, having a molecular weight ofbetween about 1000-10,000. This polyether surfactant is admixed with apolyhydric alcohol fatty acid ester containing 1-20 moles of ethyleneoxide and/or propylene oxide or such that a stable emulsion is formedupon dilution with water.

One example of such a polyether surfactant is the reaction product ofglycerol with 70 moles of propylene oxide followed by reaction with 16moles of ethylene oxide yielding a polyether surfactant having amolecular weight of about 4900. Another useful polyether surfactant isobtained by reacting sorbitol with ethylene oxide and propylene oxide.The final product having a molecular weight of about 6700 based onhydroxyl number, a cloud point in distilled water of 64° F. (1.0%soln.), and reduces surface tension of water to 37 dynes cm⁻¹ at aconcentration of 0.01% by weight.

More specifically, the antifoam/defoamer composition includes a glycerolheteropolymer or block copolymer with ethylene oxide and/or propyleneoxide such that the total molecular weight is about 800-8000, and whichcontains approximately 0-30% ethylene oxide by weight. This polyethersurfactant is admixed with a polyhydric alcohol fatty acid ester, suchas polyethylene glycol 200-600 mono and/or dioleate.

The preferred concentration of the antifoam/defoamer composition usefulin controlling entrained air and surface foam of a papermaking processis from about 0.010-10.0 lbs./ton of paper produced. Even morepreferably in the range between about 0.10-3.0 lbs./ton of paperproduced.

EXAMPLE 1

A laboratory evaluation of three defoamers Was conducted using anantifoam recirculation tester. The samples tested were as follows:

1. a 1% solution of a polyether surfactant.

2. a 1% solution of a polyethylene glycol ester (emulsifier Z).

3. a 1% solution of a blend of polyethylene glycol ester and polyethersurfactant (defoamer Y).

The antifoam and defoaming characteristics of these samples are setforth in FIG. 1 and FIG. 2, respectively. The data in FIGS. 1 and 2clearly indicates that the defoamer of the present invention (defoamerY), i.e., a blend of a polyether surfactant and a polyhydric alcoholfatty acid ester, Works effectively as an antifoam/defoamer agent.

EXAMPLE 2

The defoamer of the present invention (defoamer Y), i.e., a blend of apolyether surfactant and a polyhydric alcohol fatty acid ester, wastested against a 100% active propoxylated fatty alcohol defoamer(defoamer R). The concentration of each sample was gradually increasedfrom 0-50ppm in a groundwood thick stock at 135° Fahrenheit. The resultsset forth in FIG. 3, clearly demonstrate that the defoamer compositionof the present invention (defoamer Y) generated a much lower foam numberthan defoamer R and, as such, a much greater product performance.

EXAMPLE 3

A laboratory evaluation of four defoamers was conducted using anantifoam recirculation tester. Various defoamers were added togroundwood papermaking furnish at a dosage of 2 ppm and the foam heightwas recorded over time. The four samples were:

1. a blend of a polyhydric alcohol fatty acid ester and a polyethersurfactant (defoamer Y).

2. a polyether surfactant.

3. a polyethylene glycol ester (defoamer X).

4. a Water-based emulsion defoamer (defoamer S).

The results of the recirculation tester are set forth in FIG. 4,attached hereto. FIG. 4 clearly demonstrates the appreciable reductionin foam height during the processing of groundwood papermaking furnishWith the defoamer of the present invention (defoamer Y).

Similar results occurred when the defoamer dosages were increased to 5ppm and 10 ppm, although at lower dosages, such as 2 ppm, the defoamerof the present invention was far superior to the others tested

EXAMPLE 4

An entrained air tester was used to determine the effectiveness of theantifoam/defoamer composition of the present invention versus variousother defoamers. The following samples were run:

1. a defoamer concentrate of the polyhydric alcohol fatty acid estertype (defoamer A).

2. an oil-based particulate containing defoamer (defoamer B).

3. a blend of a polyhydric alcohol fatty acid ester and a polyethersurfactant (defoamer Y).

4. a polyether surfactant.

5. a defoamer containing hydrophobic silica and ethylene bis stearamide(defoamer C).

6. a defoamer containing fatty alcohol as the active ingredient(defoamer D).

The results are set forth in FIG. 5, attached hereto, wherein thedefoamer of the present invention (defoamer Y) demonstrated good surfacefoam and entrained air control. Defoamer A demonstrated good surfacefoam control, but poor entrained air control. The polyether surfactant,defoamer C, and defoamer D all demonstrated poor surface foam andentrained air control. Defoamer B also demonstrated good surface foamand entrained air control.

EXAMPLE 5

A laboratory evaluation of seven (7) defoaming agents was conductedusing an antifoam recirculation tester. The samples tested were:

1. a polyether surfactant (Sample 1).

2. a polyhydric alcohol fatty acid ester, such as polyethylene glycoldiester, (Sample 2).

3. a polyether surfactant and a polyhydric alcohol fatty acid ester(Sample 3).

4. a fatty alcohol-based defoamer (Sample 4).

5. an oil-based polyethylene glycol ester (Sample 5).

6. a polyethylene glycol ester defoamer (Sample 6).

7. a 100% active propoxylated fatty alcohol defoamer (Sample 7).

This evaluation was conducted on an antifoam recirculation tester withthe results thereof being set forth below in Table 1.

                  TABLE 1                                                         ______________________________________                                        Time  Blank   1        2   3     4   5     6   7                              ______________________________________                                         0    20      20       20  20    20  20    20  20                             15    24      20       20  20    20  20    20  20                             30    27      20       20  20    20  20    20  20                             45    30      20       20  20    23  21    20  20                             60    33      20       20  20    25  22    22  22                             75    33      22       20  20    26  22    22  24                             90    33      24       22  20    27  24    24  25                             105   34      25       25  20    28  27    26  25                             120   35      27       26  22    29  29    28  26                             ______________________________________                                    

The numbers 20-35 are units of measure on the recirculation testeritself. The higher the number the more foam generated. Thus, inaccordance with this analysis the antifoam/defoamer of the presentinvention (Sample 3) was the most effective defoamer over time.

While I have shown and described several embodiments in accordance withmy invention, it is to be clearly understood that the same aresusceptible to numerous changes apparent to one skilled in the art.Therefore, I do not wish to be limited to the details shown anddescribed but intend to show all changes and modifications which comewithin the scope of the appended claims.

What is claimed is:
 1. A method for controlling foam in a papermakingprocess comprising the steps of:adding to a pulp slurry and/orsuspension an antifoam/defoamer composition consisting of: 10-90% byweight of a polyether surfactant, said polyether surfactant comprisingat least one compound selected from the group consisting ofpolyoxyalkylated glycerol, polyoxyalkylated sorbitol or sorbitan,polyoxyalkylated sucrose, and isomers thereof; wherein saidpolyoxyalkylated glycerol, sorbitol, or sucrose contains ethylene oxidein the range between about 0-60 weight % and/or propylene oxide in therange between about 30-100 weight % and has a molecular weight in therange between about 1000-10,000; and 10-90% by weight of a polyhydricalcohol fatty acid ester, said polyhydric alcohol fatty acid estercomprising: a fatty acid mono and/or diester of polyethylene glycoland/or polypropylene glycol; whereby said antifoam/defoamer does notcontain any oil, amides, hydrophobic silica or silicons, therebyavoiding deposition and felt filling caused by said oil, amides,hydrophobic silica or silicone.
 2. The method according to claim 1,wherein said antifoam/defoamer composition is added in a concentrationin the range between about 0.01-10.0 pounds per ton of paper produced.3. The method according to claim 2, wherein said antifoam/defoamercomposition is added in a concentration in the range between about0.10-3.0 pounds per ton of paper produced.
 4. The method according toclaim 1, wherein said polyether surfactant is a glycerol heteropolymeror block copolymer with ethylene oxide and/or propylene oxide in anamount such that the total molecular weight of said polyether surfactantis about 1000-8000 and such that it contains between about 0-30%ethylene oxide by weight.
 5. The method according to claim 1, whereinsaid polyether surfactant is a reaction product of glycerol with 70moles of propylene oxide followed by reaction with 16 moles of ethyleneoxide, thereby forming a polyether surfactant having a molecular weightof about
 4900. 6. The method according to claim 1 wherein said polyethersurfactant is a reaction product of glycerol with ethylene oxide andpropylene oxide, thereby forming a polyether surfactant having amolecular weight of about 6700 based on hydroxyl number, a cloud pointin distilled water of 64° F., and reduces surface tension of water to 37dynes cm⁻¹ at a concentration of 0.01 % by weight.
 7. The methodaccording to claim 1, wherein said polyether surfactant has a HLB in therange between about 6-12.
 8. The method according to claim 1, whereinsaid polyhydric alcohol fatty acid ester is a polyethylene glycol monoand/or diester of fatty acids.
 9. The method according to claim 8,wherein said polyethylene glycol mono and/or diester of fatty acids areprepared by oxyalkylation or esterification of fatty acids.
 10. Themethod according to claim 8, wherein said polyethylene glycol is a monoand/or diester of fatty acid, said polyethylene glycol has a molecularweight in the range between about 100 to about
 800. 11. The methodaccording to claim 10, wherein said polyethylene glycol is a mono and/ordiester of oleic, tall oil, or stearic acids, said polyethylene glycolhas a molecular weight in the range between about 200 to about
 600. 12.The method according to claim 1, wherein said polyhydric alcohol fattyacid ester includes ethylene oxide and/or propylene oxide.
 13. Themethod according to claim 12, wherein said polyhydric alcohol fatty acidester contains between about 1-20 moles of ethylene oxide and/orpropylene oxide.
 14. The method according to claim 1, wherein saidpropylene glycol and/or polypropylene glycol is reacted with onecompound selected from the group consisting of oleic, tall oil, andtallow derived fatty acids, thereby forming said ester.
 15. The methodcomposition according to claim 1, wherein said polyhydric alcohol fattyacid ester comprises a polyhydric alcohol selected from the groupconsisting of polyethylene glycol and/or polypropylene glycol, glycerol,sorbitol or sorbitan, sucrose, and isomers thereof, reacted with eitheroleic, tall oil, castor oil, or tallow derived fatty acids.
 16. Themethod according to claim 15, wherein said polyhydric alcohol fatty acidester is further modified by alkoxylation.